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Report number 0807

BIO-REX Hartmann Bio Filter tested in a finisher facility.


The aim of this study was to document the ability of the BIO-REX Hartmann Bio Filter to reduce odour and ammonia concentrations in the outlet air from a finisher facility during the summer and, secondarily, calculate the operating costs of using the biofilter. Since the 1990s, the German company Hartmann Filter GmbH i.G. has been selling horizontal biofilters for purification of odour and ammonia in outlet air from pig facilities. In Denmark, the biofilter is sold via BIO-REX Technology ApS under the name BIO-REX Hartmann Bio Filter.

The effect of the biofilter was investigated in a facility with 250 finishers. The biofilter was placed next to the facility and was hooked up to the ventilation system of the facility. The biofilter was studied during the production of a batch of pigs transferred to the facility on August 1, 2007.

The results demonstrated that the BIO-REX Hartmann Bio Filter was capable of significantly reducing the odour and ammonia concentrations of the outlet air from the finisher facility. The odour concentration averaged 2,860 OUE/m3 before the biofilter and 575 OUE/m3 after the biofilter. The odour reduction above the filter thereby averaged 77% (95% confidence interval: 68-85). The ammonia reduction averaged 65% (95% confidence interval: 47-84) as the ammonia concentration averaged 7.2 ppm before the biofilter and 2.6 ppm after the biofilter. Furthermore, leading the air through the biofilter also reduced the concentration of hydrogen sulphide in the facility air. In terms of operating costs, a large consumption of water for moistening the biofilter and large variations in the daily consumption of water were recorded. The water consumption averaged 2.41 m3/day, which was higher than the average 1 m3/day expected by the company. This relatively large water consumption was due to problems with the moisture control as the moisture sensors were sometimes unable to record the actual moisture in the filter material. Furthermore, a large pressure loss was recorded above the filter material of 180-260 pa resulting in a large consumption of electricity. In the trial period, the consumption of electricity was 32.5 kWh per produced pig, while the consumption of electricity for running the moistening system amounted to 0.25 kWh per produced pig. The operating costs of the measurements during the summer thereby amounted to DKK 26.60 per produced pig.

After the investigation was complete, the company BIO-REX Technology ApS is still working on optimising the management of the moistening system and the construction of the biofilter with the aim of reducing the pressure loss. Danish Pig Production has not yet investigated the optimised set-up of the BIO-REX Hartmann Bio Filter, but measurements will be made when the company has demonstrated that the system functions reliably over a long period of time.

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Anders Leegaard Riis

Senior Project Manager 

Tlf.: +45 3339 4385



Thomas Ladegaard Jensen

Senior Consultant 

Tlf.: +45 3339 4938